Generally, a roller assembly cooperates with a cam through which the high pressure fuel pump is driven mechanically. In conventional high pressure fuel pumps, a roller shoe has a groove, essentially of a circular arc, for retaining a roller. Due to complex dimensional requirements of various parts of the roller assembly (e.g., the groove shape, the related shape of the roller, and the periphery shape of the roller shoe), the over-all manufacturing cost of the roller assembly is high. Thus, there remains a need in the art for a roller assembly for converting rotational movement into reciprocal movement which reduces over-all manufacturing cost.